(1) Field of the Invention
The present invention belongs to a technical field of ultrasound signal transmission and reception processing, and particularly relates to decoding of code sequences coded by pulse compression.
(2) Description of the Related Art
According to ultrasound signal transmission and reception processing, transmission signals for transducer elements constituting an ultrasound probe are generated, and also delay-and-sum is performed on each of respective reception signals output from the transducer elements by a reception beam former so as to obtain a reception beam signal to generate an ultrasound echo signal. A pixel array corresponding to one line of an ultrasound image for ultrasound diagnosis is generated from the ultrasound echo signal. Since an S/N (sound/noise) ratio of ultrasound echo signals directly influences the quality of ultrasound images, pulse compression encoding as described above has been used in order to improve the S/N ratio. According to the pulse compression encoding, two or more code sequences differing in positive and negative code are transmitted in respective two or more transmission events. In ultrasound signal reception processing, a decoding unit performs filter processing and an event correlation operation on each of respective reception signals corresponding to the two or more code sequences.